У) −3 3/5 : (−1 5/12) · (−6,8) · 9 3/8 : (−1 2/7)

Преобразуем числа: \(-3\frac{3}{5}=-\frac{18}{5}\), \(-1\frac{5}{12}=-\frac{17}{12}\), \(-6.8=-\frac{34}{5}\), \(9\frac{3}{8}=\frac{75}{8}\), \(-1\frac{2}{7}=-\frac{9}{7}\).

\[-\frac{18}{5}:\left(-\frac{17}{12}\right)\cdot\left(-\frac{34}{5}\right)\cdot\frac{75}{8}:\\left(-\frac{9}{7}\right)=\frac{1785}{2}.\]

Ответ: \(892\frac{1}{2}\).